Banca de QUALIFICAÇÃO: YARA CAMPANELLI DE MORAIS
Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.STUDENT : YARA CAMPANELLI DE MORAIS
DATE: 16/11/2022
TIME: 14:00
LOCAL: Videoconferência - Link para acesso: https://meet.google.com/ezj-oxmk-kyp
TITLE:
Blends of sulfated polysaccharides and chromium picolinate: production and evaluation of their antioxidant activity
KEY WORDS:
Sulfated polysaccharides; oxidative stress; chrome; Gracilaria birdiae
PAGES: 75
BIG AREA: Ciências Biológicas
AREA: Bioquímica
SUMMARY:
The red algae Gracilaria birdiae (GB) is cultivated and used as food in Northeastern Brazil. However, the economic potential of this alga has been little explored. One of its main components, a sulfated agaran, here called SPGb, is indicated as an agent with several properties, including as an antioxidant agent. Chromium picolinate (ChrPic) is a bioinorganic compound with recently described anti-inflammatory capacity. Blends are mixtures of one or more agents whose product tends to have greater activity/efficiency than the products that originated it. There is no record of blends containing SPGb and ChrPic. Therefore, the objective was to produce blends containing SPGb and ChrPic and to evaluate them as antioxidant agents. ChrPic was purchased commercially. SPGb was extracted from the alga after it was exposed to ultrasound waves and proteolysis and its identity was confirmed by chemical analysis and nuclear magnetic resonance (1H1D and HSQC). ChrPic (from 0.5 to 2.0 mg/mL) did not present copper or iron chelating activity, whereas SPGb (2.0 mg/mL) presented activity of 70 and 73%, for these tests, respectively. On the other hand, ChrPic (1.0 mg/mL) showed about 80% and 100% scavenging activity for superoxide and hydroxyl radicals, respectively. While SPGb (2.0 mg/mL) showed no activity. Five blends were produced (B1; B2; B3; B4; B5) whose antioxidant activity was evaluated and data indicated B5 (SPGb:ChrPic; 1:1) as the most potent blend. Comet testing demonstrated that B5 (0.1 to 0.4 mg/mL) has no genotoxic activity. B5 (0.1 to 0.4 mg/mL) and SPGb (0.02 to 0.05 mg/mL) were not cytotoxic to murine fibroblasts (3T3) and Chinese hamster ovary cells (CHO-K1) . ChrPic (0.2 mg/mL) decreased by 30% the ability of cells to reduce MTT. When 3T3 cells were exposed to H2O2 (5 mM) they showed about 50% of the ability to reduce MTT compared to cells not exposed to peroxide. The presence of H2O2 together with SPGb or ChrPic made the cells' ability to reduce MTT even smaller. On the other hand, the presence of B5 (0.05 mg/mL) protected the cells from the action of H2O2, since the MTT reduction by these cells was ~100%. When cells were exposed to SPGb, ChrPic or B5 for 24 h, and subsequently to H2O2 (5 mM), it was found that the presence of SPGb was unable to prevent the decrease in the ability of cells to reduce MTT, while cells exposed to ChrPic (0.025 mg/mL) and B5 (0.05 mg/mL) reduced MTT by 100%. In another experiment, cells were exposed to peroxide and then exposed to SPGb, ChrPic or B5 for 24 h. In this case, again SPGb was not effective in protecting cells from peroxide, while cells exposed to ChrPic (0.025 mg/mL) and B5 (0.05 mg/mL) reduced MTT by 100%. The data showed that B5 was the blend with the most potent antioxidant action, which has antioxidant activity greater than SPGb and similar activity to ChrPic, except in the test of cell exposure to peroxide concomitantly with B5, when the activity of B5 was 3 times higher. that of ChrPic. In addition, B5 did not show signs of cytotoxicity, while ChrPic did. These data point to B5 as a product to be used in future in vivo tests to confirm its antioxidant action. Also, indicate it as a possible substitute for ChrPic.
COMMITTEE MEMBERS:
Presidente - 1453487 - KATIA CASTANHO SCORTECCI
Externa ao Programa - 3309409 - KAROLINE RACHEL TEODOSIO DE MELO - UFRNExterna à Instituição - DAYANNE LOPES GOMES - IFPI